BH,

Why, why??!! Why would you call MIL? It is not for you to snoop and get info on your W through this backhand way. Stop! It isn't helping you, W, or your M at all. Back off on MIL.

If you do talk with MIL, I'd keep the call short and inquire after FIL's health. That would have been the extent of the call to MIL.